1. Field of the Invention
The invention relates to peroxide containing dentifrices stabilized against decomposition.
2. The Related Art
Peroxides are widely viewed by the dental profession as an effective treatment against gum disease. Periodontal disorders are believed to arise from infectious anaerobic microorganisms which are active in the absence of oxygen. These microorganisms can be controlled or entirely eliminated by contact with peroxides which release oxygen. According to this rationale, oxygen creates an aerobic atmosphere destructive to the microorganisms.
Facile reactivity of the peroxide benefits performance but conversely results in storage stability problems. Dentifrices containing peroxides tend to decompose within a relatively short period of time. Not only is activity lost but there can be a marked breakdown in the dentifrice's physical properties. Dentifrice viscosity is particularly adversely affected by the chemical breakdown of thickening agents. A variety of techniques have been developed to counter the problem.
U.S. Pat. No. 4,226,851 (Sompayrac) discloses oral compositions comprising hydrogen peroxide and zinc chloride wherein vitamin E is added as a stabilizing agent. U.S. Pat. No. 4,788,052 and U.S. Pat. No. 4,839,157 both to Ng et al. report aqueous hydrogen peroxide gel dentifrices stabilized with a combination of hydrophilic and hydrophobic fumed silica.
U.S. Pat. No. 5,059,417 (Williams et al.) reports on clear gel dentifrices having a criticality in their ratio of glycerol to polyoxyethylene-polyoxypropylene copolymer. Phosphoric acid is indicated to be beneficial as an acidifying agent.
Tin compounds are described in U.S. Pat. No. 5,217,710 (Williams et al.) as stabilizing fluoride induced gel decomposition.
U.S. Pat. No. 5,326,494 and U.S. Pat. No. 5,180,517, both to Woods, describe arylazo compounds, such as tartrazine, for stabilizing sodium perborate containing cleaning liquids.
U.S. Pat. No. 5,846,570 (Barrow et al.) discloses the use of dyes such as FD&C Blue 1 and FD&C Green 3 for stabilization of hydrogen peroxide containing dentifrice gels.
Yet even with the many advances in the field, there remains a need to discover improved systems. Consequently, systems have been sought for use in oral compositions that impart to the consumer satisfactory taste, contribute no disruptive influence upon rheology, and maintain active peroxide levels even under stressing temperature conditions.
Accordingly, it is an object of the present invention to provide a peroxide containing oral composition that maintains peroxide stability even at elevated temperatures over extended periods of time.
Another object of the present invention is to provide a peroxide containing oral composition that maintains viscosity even after extended storage.
These and other objects of the present invention will become more readily apparent upon consideration of the summary, detailed descriptions and examples which follow.